Confidence intervals

2. Observational studies suggest that moderate consumption of red wine may reduce the risk of heart attack. One reason may be that red wine contains polyphenols, substances that do good things to cholesterol in the blood. In an experiment, healthy men were randomly assigned to multiple groups. One group of 9 men drank half a bottle of red wine each day for two weeks. The level of polyphenols in their blood was measured before and after the two week period. Here are the percent changes in level: 3.5, 8.1, 7.4, 4.0, 0.7, 4.9, 8.4, 7.0, 5.5 For the population of all healthy men who drink this amount of red wine: [2, 16.6] Daniel J. Geiger